From: Richard Henderson <rth@twiddle.net>
To: Olivier Danet <odanet@caramail.com>,
qemu-devel <qemu-devel@nongnu.org>,
Blue Swirl <blauwirbel@gmail.com>,
Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Subject: Re: [Qemu-devel] [PATCH v2] sparc32 : Signed integer division overflow
Date: Thu, 20 Mar 2014 09:15:40 -0700 [thread overview]
Message-ID: <532B142C.9060800@twiddle.net> (raw)
In-Reply-To: <532A1A30.3040306@caramail.com>
On 03/19/2014 03:29 PM, Olivier Danet wrote:
> + if ((int32_t) x0 != x0) {
> + x0 = x0 < 0 ? 0x80000000 : 0x7fffffff;
> + overflow = 1;
> + }
Actually, there's an existing bug here that we might as well fix.
## ... the 32-bit result is sign-extended to 64 bits and
## written into register R[rd].
That 0x80000000 is not going to promote properly to 64-bits. We might as well
go ahead and use INT32_MIN and INT32_MAX here at the same time.
r~
prev parent reply other threads:[~2014-03-20 16:16 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-19 22:29 [Qemu-devel] [PATCH v2] sparc32 : Signed integer division overflow Olivier Danet
2014-03-20 15:54 ` Richard Henderson
2014-03-20 16:15 ` Richard Henderson [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=532B142C.9060800@twiddle.net \
--to=rth@twiddle.net \
--cc=blauwirbel@gmail.com \
--cc=mark.cave-ayland@ilande.co.uk \
--cc=odanet@caramail.com \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.